UV-VISIBLE SPECTROSCOPY
The document discusses UV-visible spectroscopy, including the electromagnetic spectrum, types of electronic transitions (σ-σ*, π-π*, n-σ*, n-π*), terms used (chromophore, auxochrome), absorption bands (K, R, B), and Beer-Lambert law. It provides details on the theory behind UV-visible spectroscopy and how it can be used to analyze compounds through analysis of absorption spectra. Key terms like chromophores, electronic transitions, and Beer-Lambert law are defined. Examples are given to illustrate absorption maxima for different compound classes and how shifts in maxima occur with changes to molecular structure.
Spectroscopy is the branch of science dealing the study of interaction of electromagnetic radiation with matter. OR
It is the measurement of electromagnetic radiation (EMR) absorbed or emitted when molecule or ions or atoms of a sample move from one energy state to another energy state.
Spectroscopy is the most powerful tool available for the study of atomic & molecular structure and is used in the analysis of a wide range of samples .
UV spectroscopy, Electronic transitions, law of UV, Deviations of UV, chromop...Rajesh Singh
This PowerPoint Presentation includes the principle, electronic transitions, application, chromophore, Auxochrome, Deviations and instrumentation of UV- Visible Spectrophotometer. It covers beer-lambert low and its quantitative applications. It also includes the qualitative applications in different fields of study. Presented by Rajesh Singh in GLA University Mathura.
Spectroscopy is the branch of science dealing the study of interaction of electromagnetic radiation with matter. OR
It is the measurement of electromagnetic radiation (EMR) absorbed or emitted when molecule or ions or atoms of a sample move from one energy state to another energy state.
Spectroscopy is the most powerful tool available for the study of atomic & molecular structure and is used in the analysis of a wide range of samples .
UV spectroscopy, Electronic transitions, law of UV, Deviations of UV, chromop...Rajesh Singh
This PowerPoint Presentation includes the principle, electronic transitions, application, chromophore, Auxochrome, Deviations and instrumentation of UV- Visible Spectrophotometer. It covers beer-lambert low and its quantitative applications. It also includes the qualitative applications in different fields of study. Presented by Rajesh Singh in GLA University Mathura.
Various factor affecting vibrational frequency in IR spectroscopy.vishvajitsinh Bhati
various factor affecting vibrational frequency in IR,
• Coupled vibrations
• Fermi resonance
• Electronic effects
• Hydrogen bonding
and their examples
This presentation gives you thorough knowledge about the IR Spectroscopy. This include basic principle, type of vibrations, factors influencing vibrational frequency, instrumentation and applications of IR Spectroscopy. This is the most widely used technique for identifying unknown functional group depending on the vibrational frequency.
a substance can absorb any visible light or external radiation and then again emit it. this called fluorescence and the process of reduction in fluorescence intensity is called quenching. this presentation is all about quenching of fluorescence.
IR SPECTROSCOPY, INTRODUCTION, PRINCIPLE, THEORY, FATE OF ABSORBED RADIATION, FERMI RESONANCE, FINGERPRINT REGION, VIBRATIONS, FACTORS AFFECTING ABSORPTION OF IR RADIATION, SAMPLING TECHNIQUES, APPLICATIONS OF IR SPECTROSCOPY.
Various factor affecting vibrational frequency in IR spectroscopy.vishvajitsinh Bhati
various factor affecting vibrational frequency in IR,
• Coupled vibrations
• Fermi resonance
• Electronic effects
• Hydrogen bonding
and their examples
This presentation gives you thorough knowledge about the IR Spectroscopy. This include basic principle, type of vibrations, factors influencing vibrational frequency, instrumentation and applications of IR Spectroscopy. This is the most widely used technique for identifying unknown functional group depending on the vibrational frequency.
a substance can absorb any visible light or external radiation and then again emit it. this called fluorescence and the process of reduction in fluorescence intensity is called quenching. this presentation is all about quenching of fluorescence.
IR SPECTROSCOPY, INTRODUCTION, PRINCIPLE, THEORY, FATE OF ABSORBED RADIATION, FERMI RESONANCE, FINGERPRINT REGION, VIBRATIONS, FACTORS AFFECTING ABSORPTION OF IR RADIATION, SAMPLING TECHNIQUES, APPLICATIONS OF IR SPECTROSCOPY.
Ultraviolet–visible spectroscopy or ultraviolet-visible spectrophotometry (UV-Vis or UV/Vis) refers to absorption spectroscopy or reflectance spectroscopy in the ultraviolet-visible spectral region. This means it uses light in the visible and adjacent ranges.
INTRODUCTION TO UV-VISIBLE SPECTROSCOPYJunaid Khan
UV-visible spectroscopy is the classical and the most reliable technique for qualitative and quantitative analysis of organic compounds. It involves detection of light absorbed by the sample and correlates it with concentration of the solute.
uv-visible spectroscopy also available video lecture on youtube channel name ...Pharma Rising, Bhopal
This slide contain introduction, electromagnetic radiation, lamberts beers law, principal, instrumentation, application of uv visible spectroscopy
also contain data interpretation and difference and factor which affect absorption
absorption shift and effects
UV spectroscopy is an analytical method used to detct the numbers of double and triple bonds present in dienes ,trienes and polyenes compounds.The energy corresponds to EM radiation in the ultraviolet (UV) region, 100-350 nm, and visible (VIS) regions 350-700 nm of the spectrum is known as UV spectrum.
UV-Visible spectroscopy, a versatile analytical technique used to study the interaction of molecules with light within the ultraviolet and visible regions of the electromagnetic spectrum. It is a fundamental tool in chemistry, biochemistry, and related fields for analyzing the electronic structure of molecules, determining their concentrations, and studying their behavior.
1. Principle of UV-Visible Spectroscopy:
UV-Vis spectroscopy is based on the principle that molecules absorb specific wavelengths of light due to electronic transitions.
When molecules absorb light in the UV or visible range, they move from a ground state to an excited state.
2. Instrumentation:
UV-Vis spectrophotometer is the key instrument used for this technique.
Components include a light source, sample holder, monochromator, and a detector.
The sample is placed in a cuvette, and the spectrophotometer measures the absorbance of light passing through the sample.
3. Beer-Lambert Law:
The Beer-Lambert law relates the concentration of a solution, the path length (distance that light travels through the solution), and the absorbance of light by the solution.
A = ε * c * l, where A is absorbance, ε is the molar absorptivity (a constant for a specific compound and wavelength), c is the concentration, and l is the path length.
4. Absorbance Spectra:
UV-Vis spectroscopy generates absorbance spectra, which are plots of absorbance versus wavelength.
Peaks in the spectra indicate the wavelengths of light that are absorbed by the sample, providing information about the electronic structure of the molecules.
5. Applications:
Quantitative Analysis: UV-Vis is widely used for quantitative analysis of compounds by measuring the absorbance of a sample and comparing it to a standard curve.
Identification of Compounds: The unique absorbance spectra can be used to identify compounds.
Kinetics: UV-Vis can monitor reaction kinetics by following the change in absorbance over time.
Pharmaceutical Analysis: It is crucial in quality control for pharmaceuticals.
Environmental Analysis: UV-Vis is used in environmental monitoring, such as water quality analysis.
6. Advantages:
It's a rapid and simple technique.
It can be highly sensitive for many compounds.
It is non-destructive to the sample.
7. Limitations:
It does not provide structural information about the molecules.
It may not be suitable for analyzing complex mixtures.
UV spectroscopy is a technique used to analyze the composition of a sample by measuring its absorption or reflection of ultraviolet light. The sample is placed in a UV spectrophotometer and exposed to a range of UV wavelengths. The amount of light absorbed or reflected at each wavelength is recorded and plotted as a UV spectrum. This spectrum can be used to identify specific compounds in the sample, as each compound absorbs or reflects light at different wavelengths. This technique is widely used in fields such as chemistry, biology, and environmental science to analyze a variety of samples such as drugs, food, and water.
Uv visible spectroscopy absorption methods.
INSTRUMENTAL METHODS OF ANALYSIS, B.PHARM 7TH SEM. AND FOR BSC,MSC CHEMISTRY.
This is Geeta prasad kashyap (Asst. Professor), SVITS, Bilaspur (C.G) 495001
New Directions in Targeted Therapeutic Approaches for Older Adults With Mantl...i3 Health
i3 Health is pleased to make the speaker slides from this activity available for use as a non-accredited self-study or teaching resource.
This slide deck presented by Dr. Kami Maddocks, Professor-Clinical in the Division of Hematology and
Associate Division Director for Ambulatory Operations
The Ohio State University Comprehensive Cancer Center, will provide insight into new directions in targeted therapeutic approaches for older adults with mantle cell lymphoma.
STATEMENT OF NEED
Mantle cell lymphoma (MCL) is a rare, aggressive B-cell non-Hodgkin lymphoma (NHL) accounting for 5% to 7% of all lymphomas. Its prognosis ranges from indolent disease that does not require treatment for years to very aggressive disease, which is associated with poor survival (Silkenstedt et al, 2021). Typically, MCL is diagnosed at advanced stage and in older patients who cannot tolerate intensive therapy (NCCN, 2022). Although recent advances have slightly increased remission rates, recurrence and relapse remain very common, leading to a median overall survival between 3 and 6 years (LLS, 2021). Though there are several effective options, progress is still needed towards establishing an accepted frontline approach for MCL (Castellino et al, 2022). Treatment selection and management of MCL are complicated by the heterogeneity of prognosis, advanced age and comorbidities of patients, and lack of an established standard approach for treatment, making it vital that clinicians be familiar with the latest research and advances in this area. In this activity chaired by Michael Wang, MD, Professor in the Department of Lymphoma & Myeloma at MD Anderson Cancer Center, expert faculty will discuss prognostic factors informing treatment, the promising results of recent trials in new therapeutic approaches, and the implications of treatment resistance in therapeutic selection for MCL.
Target Audience
Hematology/oncology fellows, attending faculty, and other health care professionals involved in the treatment of patients with mantle cell lymphoma (MCL).
Learning Objectives
1.) Identify clinical and biological prognostic factors that can guide treatment decision making for older adults with MCL
2.) Evaluate emerging data on targeted therapeutic approaches for treatment-naive and relapsed/refractory MCL and their applicability to older adults
3.) Assess mechanisms of resistance to targeted therapies for MCL and their implications for treatment selection
Report Back from SGO 2024: What’s the Latest in Cervical Cancer?bkling
Are you curious about what’s new in cervical cancer research or unsure what the findings mean? Join Dr. Emily Ko, a gynecologic oncologist at Penn Medicine, to learn about the latest updates from the Society of Gynecologic Oncology (SGO) 2024 Annual Meeting on Women’s Cancer. Dr. Ko will discuss what the research presented at the conference means for you and answer your questions about the new developments.
These lecture slides, by Dr Sidra Arshad, offer a quick overview of physiological basis of a normal electrocardiogram.
Learning objectives:
1. Define an electrocardiogram (ECG) and electrocardiography
2. Describe how dipoles generated by the heart produce the waveforms of the ECG
3. Describe the components of a normal electrocardiogram of a typical bipolar leads (limb II)
4. Differentiate between intervals and segments
5. Enlist some common indications for obtaining an ECG
Study Resources:
1. Chapter 11, Guyton and Hall Textbook of Medical Physiology, 14th edition
2. Chapter 9, Human Physiology - From Cells to Systems, Lauralee Sherwood, 9th edition
3. Chapter 29, Ganong’s Review of Medical Physiology, 26th edition
4. Electrocardiogram, StatPearls - https://www.ncbi.nlm.nih.gov/books/NBK549803/
5. ECG in Medical Practice by ABM Abdullah, 4th edition
6. ECG Basics, http://www.nataliescasebook.com/tag/e-c-g-basics
Title: Sense of Taste
Presenter: Dr. Faiza, Assistant Professor of Physiology
Qualifications:
MBBS (Best Graduate, AIMC Lahore)
FCPS Physiology
ICMT, CHPE, DHPE (STMU)
MPH (GC University, Faisalabad)
MBA (Virtual University of Pakistan)
Learning Objectives:
Describe the structure and function of taste buds.
Describe the relationship between the taste threshold and taste index of common substances.
Explain the chemical basis and signal transduction of taste perception for each type of primary taste sensation.
Recognize different abnormalities of taste perception and their causes.
Key Topics:
Significance of Taste Sensation:
Differentiation between pleasant and harmful food
Influence on behavior
Selection of food based on metabolic needs
Receptors of Taste:
Taste buds on the tongue
Influence of sense of smell, texture of food, and pain stimulation (e.g., by pepper)
Primary and Secondary Taste Sensations:
Primary taste sensations: Sweet, Sour, Salty, Bitter, Umami
Chemical basis and signal transduction mechanisms for each taste
Taste Threshold and Index:
Taste threshold values for Sweet (sucrose), Salty (NaCl), Sour (HCl), and Bitter (Quinine)
Taste index relationship: Inversely proportional to taste threshold
Taste Blindness:
Inability to taste certain substances, particularly thiourea compounds
Example: Phenylthiocarbamide
Structure and Function of Taste Buds:
Composition: Epithelial cells, Sustentacular/Supporting cells, Taste cells, Basal cells
Features: Taste pores, Taste hairs/microvilli, and Taste nerve fibers
Location of Taste Buds:
Found in papillae of the tongue (Fungiform, Circumvallate, Foliate)
Also present on the palate, tonsillar pillars, epiglottis, and proximal esophagus
Mechanism of Taste Stimulation:
Interaction of taste substances with receptors on microvilli
Signal transduction pathways for Umami, Sweet, Bitter, Sour, and Salty tastes
Taste Sensitivity and Adaptation:
Decrease in sensitivity with age
Rapid adaptation of taste sensation
Role of Saliva in Taste:
Dissolution of tastants to reach receptors
Washing away the stimulus
Taste Preferences and Aversions:
Mechanisms behind taste preference and aversion
Influence of receptors and neural pathways
Impact of Sensory Nerve Damage:
Degeneration of taste buds if the sensory nerve fiber is cut
Abnormalities of Taste Detection:
Conditions: Ageusia, Hypogeusia, Dysgeusia (parageusia)
Causes: Nerve damage, neurological disorders, infections, poor oral hygiene, adverse drug effects, deficiencies, aging, tobacco use, altered neurotransmitter levels
Neurotransmitters and Taste Threshold:
Effects of serotonin (5-HT) and norepinephrine (NE) on taste sensitivity
Supertasters:
25% of the population with heightened sensitivity to taste, especially bitterness
Increased number of fungiform papillae
NVBDCP.pptx Nation vector borne disease control programSapna Thakur
NVBDCP was launched in 2003-2004 . Vector-Borne Disease: Disease that results from an infection transmitted to humans and other animals by blood-feeding arthropods, such as mosquitoes, ticks, and fleas. Examples of vector-borne diseases include Dengue fever, West Nile Virus, Lyme disease, and malaria.
Couples presenting to the infertility clinic- Do they really have infertility...Sujoy Dasgupta
Dr Sujoy Dasgupta presented the study on "Couples presenting to the infertility clinic- Do they really have infertility? – The unexplored stories of non-consummation" in the 13th Congress of the Asia Pacific Initiative on Reproduction (ASPIRE 2024) at Manila on 24 May, 2024.
ARTIFICIAL INTELLIGENCE IN HEALTHCARE.pdfAnujkumaranit
Artificial intelligence (AI) refers to the simulation of human intelligence processes by machines, especially computer systems. It encompasses tasks such as learning, reasoning, problem-solving, perception, and language understanding. AI technologies are revolutionizing various fields, from healthcare to finance, by enabling machines to perform tasks that typically require human intelligence.
New Drug Discovery and Development .....NEHA GUPTA
The "New Drug Discovery and Development" process involves the identification, design, testing, and manufacturing of novel pharmaceutical compounds with the aim of introducing new and improved treatments for various medical conditions. This comprehensive endeavor encompasses various stages, including target identification, preclinical studies, clinical trials, regulatory approval, and post-market surveillance. It involves multidisciplinary collaboration among scientists, researchers, clinicians, regulatory experts, and pharmaceutical companies to bring innovative therapies to market and address unmet medical needs.
These simplified slides by Dr. Sidra Arshad present an overview of the non-respiratory functions of the respiratory tract.
Learning objectives:
1. Enlist the non-respiratory functions of the respiratory tract
2. Briefly explain how these functions are carried out
3. Discuss the significance of dead space
4. Differentiate between minute ventilation and alveolar ventilation
5. Describe the cough and sneeze reflexes
Study Resources:
1. Chapter 39, Guyton and Hall Textbook of Medical Physiology, 14th edition
2. Chapter 34, Ganong’s Review of Medical Physiology, 26th edition
3. Chapter 17, Human Physiology by Lauralee Sherwood, 9th edition
4. Non-respiratory functions of the lungs https://academic.oup.com/bjaed/article/13/3/98/278874
Tom Selleck Health: A Comprehensive Look at the Iconic Actor’s Wellness Journeygreendigital
Tom Selleck, an enduring figure in Hollywood. has captivated audiences for decades with his rugged charm, iconic moustache. and memorable roles in television and film. From his breakout role as Thomas Magnum in Magnum P.I. to his current portrayal of Frank Reagan in Blue Bloods. Selleck's career has spanned over 50 years. But beyond his professional achievements. fans have often been curious about Tom Selleck Health. especially as he has aged in the public eye.
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Introduction
Many have been interested in Tom Selleck health. not only because of his enduring presence on screen but also because of the challenges. and lifestyle choices he has faced and made over the years. This article delves into the various aspects of Tom Selleck health. exploring his fitness regimen, diet, mental health. and the challenges he has encountered as he ages. We'll look at how he maintains his well-being. the health issues he has faced, and his approach to ageing .
Early Life and Career
Childhood and Athletic Beginnings
Tom Selleck was born on January 29, 1945, in Detroit, Michigan, and grew up in Sherman Oaks, California. From an early age, he was involved in sports, particularly basketball. which played a significant role in his physical development. His athletic pursuits continued into college. where he attended the University of Southern California (USC) on a basketball scholarship. This early involvement in sports laid a strong foundation for his physical health and disciplined lifestyle.
Transition to Acting
Selleck's transition from an athlete to an actor came with its physical demands. His first significant role in "Magnum P.I." required him to perform various stunts and maintain a fit appearance. This role, which he played from 1980 to 1988. necessitated a rigorous fitness routine to meet the show's demands. setting the stage for his long-term commitment to health and wellness.
Fitness Regimen
Workout Routine
Tom Selleck health and fitness regimen has evolved. adapting to his changing roles and age. During his "Magnum, P.I." days. Selleck's workouts were intense and focused on building and maintaining muscle mass. His routine included weightlifting, cardiovascular exercises. and specific training for the stunts he performed on the show.
Selleck adjusted his fitness routine as he aged to suit his body's needs. Today, his workouts focus on maintaining flexibility, strength, and cardiovascular health. He incorporates low-impact exercises such as swimming, walking, and light weightlifting. This balanced approach helps him stay fit without putting undue strain on his joints and muscles.
Importance of Flexibility and Mobility
In recent years, Selleck has emphasized the importance of flexibility and mobility in his fitness regimen. Understanding the natural decline in muscle mass and joint flexibility with age. he includes stretching and yoga in his routine. These practices help prevent injuries, improve posture, and maintain mobilit
Explore natural remedies for syphilis treatment in Singapore. Discover alternative therapies, herbal remedies, and lifestyle changes that may complement conventional treatments. Learn about holistic approaches to managing syphilis symptoms and supporting overall health.
TEST BANK for Operations Management, 14th Edition by William J. Stevenson, Ve...kevinkariuki227
TEST BANK for Operations Management, 14th Edition by William J. Stevenson, Verified Chapters 1 - 19, Complete Newest Version.pdf
TEST BANK for Operations Management, 14th Edition by William J. Stevenson, Verified Chapters 1 - 19, Complete Newest Version.pdf
2. Electromagnetic radiation
Energy of an EMR
Electromagnetic spectrum & it’s regions
Spectroscopy & it’s types
Colorimetry
UV-spectroscopy
Electronic transitions
Terms used in UV-Visible spectroscopy
Absorption band & it’s types
Beer lambert’s law & it’s deviations
⓫ Reference
2
3. Electromagnetic radiation is a type of energy that is
transmitted through space at enormous velocities.
Radiant energy has wave nature and being associated
with electric as well as magnetic field,these radiations
are called electromagnetic radiation.
Electromagnetic radiation has it’s origin in atomic and
molecular processes.
3
4. The field may be represented as electric and magnetic
vectors oscillating in mutually perpendicular planes.
4
5. The energy of an EMR can be given by the following
equation:
Where E= Energy of radiation
h=Planck’s constant
µ=Frequency of radiation
E=hµ
5
6. Frequency(µ)= c/λ
Where c=velocity of light in vacuum
λ= wavelength
:-Hence, E=hµ
Therefore,energy of a radiation depends upon frequency
and wavelength of radiation.
E=hc/λ
6
7. The arrangement obtained by arranging various types
of electromagnetic waves or radiations in order of their
increasing wavelegth or decreasing frequencies is
called electromagnetic spectrum.
The electromagnetic spectrum is divided into a
number of regions; these are artificial divisions in the
sense that they have been defined solely as a result of
differences in the instrumentation required for
producing and detecting radiation of a given frequency
range.
7
11. Spectroscopy is the measurement and
interpretation of electromagnetic radiation
absorbed or emitted when the molecules or
atoms or ions of a sample moves from one
energy state to another energy state
SPECTROSCOPY
11
12. 1) Atomic spectroscopy :
Here,the changes in energy takes
place at atomic level.
Eg: Atomic absorption spectroscopy, Flame
photometry
2)Molecular spectroscopy :
Here,the changes in energy takes
place at molecular level.
Eg: UV spectroscopy,colorimetry,infra red
spectroscopy
12
13. Absorption spectrophotometry can be
defined as the measurement of absorption of radiant
energy by various substances.It involves the
measurement of absorptive capacity for radiant energy
in the visible,UV and IR regions of the spectrum.
13
14. o λ- 400-800nm
o Coloured substance absorbs light of different λ in
different manner and hence get an absorption
curve
o The λ at which maximum absorption takes place is
called as λmax
o λmax is characteristic for every coloured substance
o On plotting a graph of concentration v/s
absorbance,we get a calibration curve that is useful
in determining the concentration or amount of a
drug substance in the given sample solution. 14
16. UV spectroscopy is concerned with the study of absorption
of uv radiation which ranges from 200-400nm.
Valence electrons absorb the energy thereby molecules
undergoes transition from ground state to excited
state.
This absorption is characteristic and depends on the
nature of electrons present.
Types of electrons
σ electrons: in saturated compounds
π electrons: in unsaturated compounds
n electrons: in non bonded electrons
16
18. σ electron from orbital is excited to corresponding
anti-bonding orbital σ*.
The energy required is large for this transition.
The organic compounds in which all the valence shell
electrons are involved in the formation of σ bond do
not show absorption in normal uv region (200-400nm)
This transition is observed with saturated compounds.
1) σ-σ*
18
19. Eg: Methane(CH₄) has C-H bond only and can undergo σ-
σ* transition and shows absorption maxima at 122nm.
The usual spectroscopic technique cannot be used below
200 nm.
To study this high energy transition,the entire region
should be evacuated (Vacuum uv region)
Here,the excitation ocuurs with net retention of electronic
spin
This region is less informative
19
20. π electron in a bonding orbital is excited to
corresponding anti-bonding orbital π*.
Energy required is less when compared to n-σ*
Compounds containing multiple bonds like
alkenes,alkynes,carbonyls,nitriles,aromatic
compounds etc undergo π-π* transition.
Eg:Alkenes generally absorb in the region 170-205nm.
2) π-π*
20
21. Absorption usually occurs in the ordinary uv
spectrophotometer
Absorption bands in unconjugated alkenes (170-
190nm)
Absorption bands in carbonyls (180 nm)
Introduction of alkyl group in olefinic linkage
produces bathochromic shift
21
22. Saturated compounds containing one hetero atom
with unshared pair of electrons(n) like O,N,S and
halogens are capable of n-σ* transition.
These transition require less energy than σ-σ*
transition.
In saturated alkyl halides, the energy required for
transition decrease with increase in the size of halogen
atom (or decrease in electronegativity)
3) n-σ*
22
23. Eg:Methyl chloride has a λmax of 173nm.
Methyl iodide has a λmax of 258nm.
This type of transition is very sensitive to hydrogen
bonding
Eg: Alcohol & amines
Hydrogen bonding shift the uv absorptions to
shorter wavelength.
23
24. An electron from non-bonding orbital is promoted to
anti-bonding π* orbital.
Compounds containing double bonds involving
hetero atoms(C=O,N=O) undergo such type of
transitions.
This transition require minimum energy out of all
transitions and shows absorption band at longer
wavelength around 300nm.
4) n-π*
24
25. Eg:Saturated aldehydes shows both type of transitions
(n-π*, π-π*) at {low energy and high energy}
around 290 and 180 nm.
25
27. Chromophore is defined as the nucleus or any
isolated covalently bonded group responsible for the
absorption of light radiation.
Any group which exhibits absorption of
electromagnetic radiations in the visible or ultraviolet
region.
C=C , C=O ,NO2 etc
Some of the important chromophores are
carbonyls,acids,esters,nitrile,ethylenic groups.
27
29. These are co-ordinatively saturated or un-saturated
groups which themselves do not absorb radiations,but
when present alongwith a chromophore enhances the
absorbing properties of chromophore.
Also known as colour enhancing group.
All auxochromes have one or more non-bonding pair
of electrons.
-NH2 ,-OH ,-OR,-COOH etc
It extend the conjugation of a chromophore by sharing
the non-bonding electrons. 29
32. When the absorption maxima(λmax)of a compound
shifts to longer wavelength,it is known as
bathochromic shift or red shift.
The effect is due to the presence of auxochrome or by
change of solvent.
Eg: The n-π* transition for carbonyl compounds
experiences bathochromic shift when the polarity of
solvent is decreased.
1) Bathochromic shift(red shift)
32
33. When the absorption maxima (λmax) of a compound
shifts to a shorter wavelength,it is known as
hypsochromic shift or blue shift.
The effect is due to the presence of a group causes
removal of conjugation or by change of solvent.
2) Hypsochromic shift(blue shift)
33
34. Eg:
Aniline shows blue shift in acidic medium since it loses
conjugation. Aniline(280nm) & Anilinium ion (-
203nm).
34
39. The spectrum consist of sharp peaks and each peak will
correspond to the promotion of electron from one
electronic level to another.
During promotion,the electron moves from a given
vibrational and rotational level within one electronic mode
to the other within the next electronic mode.
Thus,there will be a large no of possible transitions
Hence,not just one but a large no. of wavelengths which
are close enough will be absorbed resulting in the
formation of bands 39
40. 1) K –Band
K-Bands originate due to π-π* transition from a
compound containing a conjugated system
Such type of bands arise in compounds like
dienes,polyenes and enones etc.
Compound Transition λmax(nm) εmax
Acetophenone π-π* 240 13,000
1,3-butadiene π-π* 217 21,000
40
41. R-Band transition originate due to n-π* transition of a
single chromophoric group and having atleast one
lone pair of electrons on the hetero atom
These are less intense with εmax value below 100
Compound Transition λmax(nm) εmax
Acetone n-π* 270 15
Acetaldehyde n-π* 293 12
41
42. Such type of bands arise due to π-π* transition in
aromatic or hetero-aromatic molecules.
Benzene shows absorption peaks between 230-
270nm.when a chromophoric group is attached to the
benzene ring ,the B-Bands are observed at longer
wavelengths than the more intense K-Bands.
Compound Transition λmax(nm) εmax
Benzene π-π* 255 215
Phenol π- π* 270 1450
42
43. E-Band originate due to the electronic transitions in
the benzenoid systems of three ethylenic bonds which
are in closed cyclic conjugation.
These are further characterized as E1 and E2 bands
E1 band which appear at shorter wavelength is usually
more intense than the E2 band for the same
compound which appears at longer wavelength.
Compound E1 Band E1 Band E2 Band E2 Band
λmax(nm) εmax λmax(nm) εmax
Benzene 184 50,000 204 79,000
Napthalene 221 133,000 286 9,300
43
45. BEER’S LAW
According to this law,when a beam of monochromatic
radiation is passed through a solution of absorbing species,the
intensity of beam of monochromatic light decreases exponentially
with increase in concentration of absorbing species
LAMBERT’S LAW
Lambert’s law states that the rate of decrease of
intensity of monochromatic light with the thickness of the
medium is directly proportional to the intensity of incident
light.
-dI/dc α I
-dI/dt α I
45
46. According to beer’s law,
-dI α I
dc
The decrease in the intensity of light (I) with
concentration(c) is proportional to intensity of
incident light(I)
-dI = K.I { removing & introducing the
dc constant of proportionality
“K”}
-dI = K.dc { rearranging terms}
I
46
47. On Integrating the equation,
-∫dI = K.∫dc
I
-ln I = K.c + b { b constant of integration}
When concentration =0, there is no absorbance,Hence I=I₀
Substituting in equation
-ln I₀ = K*0+b
-ln I₀ = b
Substituting the value of b in equation
-ln I = K.c-ln I₀
ln I₀ - ln I = Kc { since log A-logB = log A }
B
ln I₀ = Kc
I
47
48. I₀ = ekc { removing natural log }
I
I = e-kc {making inverse on both sides}
I₀
I = I₀e-kc [equation for beer’s law]
According to lambert’s law,
-dI α I
dt
This eqn can be simplified by replacing ‘c’ with ‘t’ in
I = I₀e-kt
Eqn & can be combined to get I = I₀e-kct 48
49. Converting natural log to base 10 & K= k x 0.4343
I = ₁₀-kct { rearranging terms }
I₀
I₀ = ₁₀kct { inverse on both sides}
I
Taking log on both sides ,
log I₀ = Kct
I
Here, Transmittance T = I₀ , Absorbance,A = log 1
I T
49
50. A = log 1
T
A = log 1 { Since T = I₀ }
I/I₀ I
A =log I₀
I
Using eqn & , since A =log I₀ and log I₀ = Kct ,
I I
A= Kct
Instead of K, we can use ε
A = εct { Mathematical eqn for beer lambert’s
law}
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53. There are 3 types of deviations usually observed
A)The real limitation of the law is that the beer’s law is
successful in describing the absorption behaviour of
dilute solutions only.
B)CHEMICAL DEVIATIONS:
Association of molecules
This can be explained by taking the examples of
methylene blue at small concentration(10‾⁵ molar) and
at concentration above 10‾⁵molar.
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54. Dissociation of molecules
This can be explained by the fact that dichromate
ions posses their maximum absorbance at 450nm
which is orange in colour .But upon dilution,it will be
dissociated to chromate ions having maximum
absorbance at 410nm which is yellow in colour.
This law is not valid in case if the absorbing material
is coagulated into a small number of large units.
This law shows deviation if the absorbing material at
the required wavelength contains presence of
impurities.
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55. This law is not applicable in case of suspension.
C)INSTRUMENTAL DEVIATIONS:
Strict adherence of an absorbing system to this law is
observed only when the radiation used is monochromatic.
Stray radiation,slit width also causes deviation.
Hence,the reasons for the deviation depends on
environment such as temperature,pressure,solvent,
refractive index of the sample
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